Former FBI agent Ali Soufan interrogated dozens of Al-Qaida members and other extremists in the wake of the Sept. 11 attacks. He says he got valuable information by preparing carefully for interviews and building rapport with his subjects. When CIA contractors used coercive techniques — like waterboarding — Soufan says subjects ceased cooperating, or gave bad information to make the torment stop. Soufan’s 2011 memoir about his experiences appeared with large portions redacted by the CIA. After a legal battle, the redacted material is now restored in a new version, called ‘Black Banners (Declassified).’